About

Jeroen Tromp is the Blair Professor of Geology, Professor of Geosciences, and Applied and Computational Mathematics at Princeton University. He joined the Department of Geosciences in July 2008, coming from the California Institute of Technology, where he served as the Director of the Seismological Laboratory and was the McMillan Professor of Geophysics. Tromp's academic background includes a Ph.D. (1992) and an M.S. (1990) in Geophysics from Princeton University, and a B.Sc. (1988) in Geophysics from the University of Utrecht in the Netherlands, his native country. His previous academic appointments include a faculty position at Harvard University from 1992 to 2000. His primary research areas are in Theoretical & Computational Seismology, with topics including surface waves, free oscillations, body waves, seismic tomography, numerical simulations of 3-D wave propagation, and seismic hazard assessment. Tromp has contributed to the field through his work on seismic wave modeling and analysis, and in collaboration with the late Princeton Geosciences faculty member Tony Dahlen, he published the book 'Theoretical Global Seismology.' He also serves as the Director of the Princeton Institute for Computational Science and Engineering (PICSciE). His research aims to advance understanding of Earth's interior through computational seismology techniques.

Research topics

• Geology
• Seismology
• Geophysics
• Physics
• Astrobiology
• Medicine
• Geodesy
• Surgery
• Internal medicine
• Oceanography
• Optics

Selected publications

• Metric-free gravitation from geometrical defects

  Classical and Quantum Gravity · 2026-01-19

  articleOpen access1st authorCorresponding

  Abstract We develop a metric-free theory of gravitation generated by geometrical defects. Spacetime geometry is described by a velocity-distortion coframe <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msup> <mml:mi>β</mml:mi> <mml:mi>a</mml:mi> </mml:msup> <mml:mo>=</mml:mo> <mml:msup> <mml:mi>ψ</mml:mi> <mml:mi>a</mml:mi> </mml:msup> <mml:msub> <mml:mrow/> <mml:mi>μ</mml:mi> </mml:msub> <mml:mstyle scriptlevel="0"/> <mml:mrow> <mml:mi mathvariant="normal">d</mml:mi> </mml:mrow> <mml:msup> <mml:mi>φ</mml:mi> <mml:mi>μ</mml:mi> </mml:msup> </mml:mrow> </mml:math> and a spin-bend-twist connection <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msup> <mml:mi>κ</mml:mi> <mml:mi>a</mml:mi> </mml:msup> <mml:msub> <mml:mrow/> <mml:mi>b</mml:mi> </mml:msub> <mml:mo>=</mml:mo> <mml:msup> <mml:mi>ψ</mml:mi> <mml:mi>a</mml:mi> </mml:msup> <mml:msub> <mml:mrow/> <mml:mi>μ</mml:mi> </mml:msub> <mml:mstyle scriptlevel="0"/> <mml:mrow> <mml:mi mathvariant="normal">d</mml:mi> </mml:mrow> <mml:mo stretchy="false">(</mml:mo> <mml:msup> <mml:mi>ψ</mml:mi> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> <mml:mo stretchy="false">)</mml:mo> <mml:msup> <mml:mrow/> <mml:mi>μ</mml:mi> </mml:msup> <mml:msub> <mml:mrow/> <mml:mi>b</mml:mi> </mml:msub> </mml:mrow> </mml:math> , defined in terms of the motion field ϕ µ and the intrinsic deformation field <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msup> <mml:mi>ψ</mml:mi> <mml:mi>a</mml:mi> </mml:msup> <mml:msub> <mml:mrow/> <mml:mi>μ</mml:mi> </mml:msub> </mml:mrow> </mml:math> . Their field strengths are the intrinsic torsion <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msup> <mml:mi mathvariant="normal">Σ</mml:mi> <mml:mi>a</mml:mi> </mml:msup> <mml:mo>=</mml:mo> <mml:mrow> <mml:mi mathvariant="normal">d</mml:mi> </mml:mrow> <mml:msup> <mml:mi>β</mml:mi> <mml:mi>a</mml:mi> </mml:msup> <mml:mo>+</mml:mo> <mml:msup> <mml:mi>κ</mml:mi> <mml:mi>a</mml:mi> </mml:msup> <mml:msub> <mml:mrow/> <mml:mi>b</mml:mi> </mml:msub> <mml:mo>∧</mml:mo> <mml:msup> <mml:mi>β</mml:mi> <mml:mi>b</mml:mi> </mml:msup> </mml:mrow> </mml:math> and intrinsic curvature <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msup> <mml:mi mathvariant="normal">Λ</mml:mi> <mml:mi>a</mml:mi> </mml:msup> <mml:msub> <mml:mrow/> <mml:mi>b</mml:mi> </mml:msub> <mml:mo>=</mml:mo> <mml:mrow> <mml:mi mathvariant="normal">d</mml:mi> </mml:mrow> <mml:msup> <mml:mi>κ</mml:mi> <mml:mi>a</mml:mi> </mml:msup> <mml:msub> <mml:mrow/> <mml:mi>b</mml:mi> </mml:msub> <mml:mo>+</mml:mo> <mml:msup> <mml:mi>κ</mml:mi> <mml:mi>a</mml:mi> </mml:msup> <mml:msub> <mml:mrow/> <mml:mi>c</mml:mi> </mml:msub> <mml:mo>∧</mml:mo> <mml:msup> <mml:mi>κ</mml:mi> <mml:mi>c</mml:mi> </mml:msup> <mml:msub> <mml:mrow/> <mml:mi>b</mml:mi> </mml:msub> </mml:mrow> </mml:math> . The fundamental field equations <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msup> <mml:mi mathvariant="normal">Σ</mml:mi> <mml:mi>a</mml:mi> </mml:msup> <mml:mo>=</mml:mo> <mml:msup> <mml:mi>α</mml:mi> <mml:mi>a</mml:mi> </mml:msup> </mml:mrow> </mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:msup> <mml:mi mathvariant="normal">Λ</mml:mi> <mml:mi>a</mml:mi> </mml:msup> <mml:msub> <mml:mrow/> <mml:mi>b

  PublisherDOI

• Theoretical and Computational Seismology

  Princeton University Press eBooks · 2025-03-12 · 1 citations

  book1st authorCorresponding

  An authoritative, self-contained reference text on theoretical and computational seismology Over the past several decades, computational advances have revolutionized seismology, making it possible to simulate seismic wave propagation in complex Earth models and create detailed images of the planet&rsquo;s interior. This cutting-edge text introduces students and scholars to the fundamentals, techniques, and applications of this exciting field of research and discovery. After establishing a strong foundation in continuum mechanics, the book presents the fundamentals of theoretical seismology, providing a basis for subsequent forward and inverse modeling grounded in numerical methods, and then focuses on computational seismology, investigating numerical solutions to seismic wave equations. The adjoint-state method is covered next, along with applications of this technique to waveform inversions across scales, after which the book concludes with a set of appendixes that provide a primer to differential geometry and tensor calculus, which are used throughout the book to explain the fundamental concepts of deformation, strain, and stress from both Eulerian and Lagrangian perspectives. Including over 150 student-tested exercises, the book is an essential resource for motivated students and scholars seeking to master the state of the art of theoretical and computational seismology. Establishes a strong foundation through a geometric analysis of continuum mechanics Reveals how linearizing the resulting equations of motion enables the simulation of seismic wave propagation across nine decades of frequencies and wavelengths Demonstrates how to leverage the capabilities of simulations to create detailed tomographic images from the information embedded in seismographic recordings Covers diverse application areas, including seismology, helioseismology, underwater acoustics, medical imaging, and nondestructive testing Features a wealth of exercises (with online solutions) Includes a comprehensive set of appendixes on differential geometry and tensor calculus An ideal textbook for graduate students studying theoretical seismology, computational seismology, or optimization and inverse problems An essential reference for researchers and scholars

  PublisherDOI

• Theoretical and Computational Seismology

  Princeton University Press eBooks · 2025-07-01

  book1st authorCorresponding
  PublisherDOI

• On the importance of horizontal components in source-encoded elastic full-waveform inversion: Multicomponent ocean-bottom-node data

  The Leading Edge · 2025-05-01

  articleSenior author

  Abstract Elastic full-waveform inversion (EFWI) is a state-of-the-art seismic tomographic method. Recent advances in technology and instrumentation, combining crosstalk-free source-encoded FWI (SE-FWI) with multicomponent marine data acquisition using ocean-bottom nodes (OBNs), enable full-physics wave propagation and parameter inversion without the computational burden of traditional FWI. With OBN acquisition, P waves, S waves, and P-to-S conversions are recorded. It is not well understood to what extent adding horizontal components to SE-FWI improves the resolution of subsurface modeling. We assess their potential for the reconstruction of shear and compressional wave speeds (VP and VS) by using a synthetic data set modeled after a recently acquired OBN survey in the North Sea. We perform synthetic inversion tests to design suitable strategies that leverage the information recorded in the horizontal components of the data to improve the reconstructed model resolution laterally and in depth. We advocate for a hierarchical inversion approach to recover the elastic parameters. We exploit the P and P-to-S converted waves recorded on the horizontal components to robustly reconstruct both VP and VS. Adding horizontal components to the SE-FWI modeling workflow results in improved spatial resolution, enhanced depth coverage, and more accurate elastic wave speed estimates.

  PublisherDOI

• 2D Near‐Surface Full‐Waveform Tomography Reveals Bedrock Controls on Critical Zone Architecture

  Earth and Space Science · 2024-02-01 · 10 citations

  articleOpen accessSenior author

  Abstract For decades, seismic imaging methods have been used to study the critical zone, Earth's thin, life‐supporting skin. The vast majority of critical zone seismic studies use traveltime tomography, which poorly resolves heterogeneity at many scales relevant to near‐surface processes, therefore limiting progress in critical zone science. Full‐waveform tomography can overcome this limitation by leveraging more seismic data and enhancing the resolution of geophysical imaging. In this study, we apply 2D full‐waveform tomography to match the phases of observed seismograms and elucidate previously undetected heterogeneity in the critical zone at a well‐studied catchment in the Laramie Range, Wyoming. In contrast to traveltime tomograms from the same data set, our results show variations in depth to bedrock ranging from 5 to 60 m over lateral scales of just tens of meters and image steep low‐velocity anomalies suggesting hydrologic pathways into the deep critical zone. Our results also show that areas with thick fractured bedrock layers correspond to zones of slightly lower velocities in the deep bedrock, while zones of high bedrock velocity correspond to sharp vertical transitions from bedrock to saprolite. By corroborating these findings with borehole imagery, we hypothesize that lateral changes in bedrock fracture density majorly impact critical zone architecture. Borehole data also show that our full‐waveform tomography results agree significantly better with velocity logs than previously published traveltime tomography models. Full‐waveform tomography thus appears unprecedentedly capable of imaging the spatially complex porosity structure crucial to critical zone hydrology and processes.

  PublisherOA PDFDOI

• GLAD-M35: a joint P and S global tomographic model with uncertainty quantification

  Geophysical Journal International · 2024-08-05 · 41 citations

  articleOpen access

  SUMMARY We present our third and final generation joint P and S global adjoint tomography (GLAD) model, GLAD-M35, and quantify its uncertainty based on a low-rank approximation of the inverse Hessian. Starting from our second-generation model, GLAD-M25, we added 680 new earthquakes to the database for a total of 2160 events. New P-wave categories are included to compensate for the imbalance between P- and S-wave measurements, and we enhanced the window selection algorithm to include more major-arc phases, providing better constraints on the structure of the deep mantle and more than doubling the number of measurement windows to 40 million. Two stages of a Broyden–Fletcher–Goldfarb–Shanno (BFGS) quasi-Newton inversion were performed, each comprising five iterations. With this BFGS update history, we determine the model’s standard deviation and resolution length through randomized singular value decomposition.

  PublisherOA PDFDOI

• Full-waveform tomography reveals iron spin crossover in Earth’s lower mantle

  Nature Communications · 2024-03-04 · 11 citations

  articleOpen accessSenior author

  Three-dimensional models of Earth's seismic structure can be used to identify temperature-dependent phenomena, including mineralogical phase and spin transformations, that are obscured in 1-D spherical averages. Full-waveform tomography maps seismic wave-speeds inside the Earth in three dimensions, at a higher resolution than classical methods. By providing absolute wave speeds (rather than perturbations) and simultaneously constraining bulk and shear wave speeds over the same frequency range, it becomes feasible to distinguish variations in temperature from changes in composition or spin state. We present a quantitative joint interpretation of bulk and shear wave speeds in the lower mantle, using a recently published full-waveform tomography model. At all depths the diversity of wave speeds cannot be explained by an isochemical mantle. Between 1000 and 2500 km depth, hypothetical mantle models containing an electronic spin crossover in ferropericlase provide a significantly better fit to the wave-speed distributions, as well as more realistic temperatures and silica contents, than models without a spin crossover. Below 2500 km, wave speed distributions are explained by an enrichment in silica towards the core-mantle boundary. This silica enrichment may represent the fractionated remains of an ancient basal magma ocean.

  PublisherOA PDFDOI

• Parsimonious Green function data bases for global centroid moment tensor inversions

  Geophysical Journal International · 2024-12-19 · 5 citations

  articleOpen accessSenior author

  SUMMARY The calculation of synthetic seismograms for global centroid moment tensor (GCMT) inversions relies on advanced 3-D Earth models. However, use of the path-average approximation for mode summation and surface-wave ray theory limits the method’s accuracy. This can cause incorrect predictions of ground motion amplitude and polarization, and other unaccounted-for effects, which can bias the estimated earthquake parameters. To address this issue, we have developed a new and efficient way to calculate, store and access high-fidelity, long-period synthetic seismograms for state-of-the-art 3-D tomographic Earth models. We adapted the spectral-element wave-equation solver SPECFEM3D_GLOBE to generate a data base of Green functions on a global, sparse spectral-element grid of hypocenters for a large set of 180 station locations, using source–receiver reciprocity to speed up the calculation. The seismograms are organized and stored in a format that facilitates rapid access to a particular source region and stations of the Global Seismographic Network. Seismograms for any centroid location can be calculated efficiently via spatial interpolation without losing accuracy compared to full forward calculation. As a proof-of-concept, we perform $\sim$9000 CMT inversions using the Sawade et al. approach, with GCMT solutions as starting models and without restriction on the number of iterations. Although the location updates are consistent with Sawade et al., we find a reduction in non-double-couple components in all types of events except for shallow strike-slip events. Given these encouraging results for future routine implementation, we present a first test and an outlook for routine 3-D GCMT analysis.

  PublisherOA PDFDOI

• Tilted transverse isotropy in Earth’s inner core

  Nature Geoscience · 2024-09-27 · 1 citations

  articleOpen access
  PublisherOA PDFDOI

• Laplace-domain crosstalk-free source-encoded elastic full-waveform inversion using time-domain solvers

  Geophysics · 2024-01-07 · 4 citations

  articleSenior author

  ABSTRACT Crosstalk-free source-encoded elastic full-waveform inversion (FWI) using time-domain solvers demonstrates skill and efficiency at conducting seismic inversions involving multiple sources and receivers with limited computational resources. A drawback of common formulations of the procedure is that, by sweeping through the frequency domain randomly at a rate of one or a few sparsely sampled frequencies per shot, it is difficult to simultaneously incorporate time-selective data windows, as necessary for the targeting of arrivals or wave packets during the various stages of the inversion. Here, we solve this problem by using the Laplace transform of the data. Using complex-valued frequencies allows for damping the records with flexible decay rates and temporal offsets that target specific traveltimes. We present the theory of crosstalk-free source-encoded FWI in the Laplace domain, develop the details of its implementation, and illustrate the procedure with numerical examples relevant to exploration-scale scenarios.

  PublisherDOI

Recent grants

• Spectral-Element Simulations of Seismic Wave Propagation

  NSF · $686k · 2003–2007

• EarthCube Building Blocks: Collaborative Proposal: The Power of Many: Ensemble Toolkit for Earth Sciences

  NSF · $340k · 2016–2020

• Toward Seismic Tomography Based Upon Adjoint Methods

  NSF · $542k · 2008–2011

• Toward Exascale Global Adjoint Tomography

  NSF · $547k · 2017–2019

• G8 Initiative: Modeling Earthquakes and Earth's Interior Based Upon Exascale Simulations of Seismic Wave Propagation

  NSF · $500k · 2011–2015

Frequent coauthors

• Dimitri Komatitsch

  Centre National de la Recherche Scientifique

  163 shared

• E. Bozdağ

  67 shared

• Daniel Peter

  King Abdullah University of Science and Technology

  52 shared

• Matthieu Lefèbvre

  36 shared

• Wenjie Lei

  Google (United States)

  34 shared

• J. X. Mitrovica

  30 shared

• Carl Tape

  30 shared

• Hiroo Kanamori

  29 shared

Labs

• GeosciencesPI

Education

• PhD, Geophysics

  Princeton University

  1992

• BS, Geophysics

  Universiteit Utrecht

  1988

Awards & honors

• Outstanding Student Presentation Award from AGU